For games, I would recommend C++, C#, or Java.
They have good libraries for games already created.
C++: SFML and SDL
C#: OpenTK and XNA
Java: LWJGL and Slick (Which uses LWJGL)
This seems to be awesome. I used XNA to build a Xbox 360 game for my dissertation. I really enjoyed working with XNA and this will allow me to build something that can run on mobile devices and Win8... awesome!
I guess games are the best choice... I can use all those cool algorithms that I've learned a long time ago (which don't really come as useful in web development) and at the end of the day I have a game which I can publish and who knows.. maybe make some beer money :D